Determination Of Arsenic And Lead In Shellfish By Capillary Electrophoresis With Inductively Coupled Plasma Mass Spectrometry And Risk Assessment

Objective: A method for the detection of trace As(III),As(V),monomethylarsonic acid(MMA),dimethylarsinic acid(DMA),arsenocholine(As C) and arsenobetaine(As B) and Pb(II), Triethyllead(TEL) and Trimethyllead(TML) in shellfish, by capillary electrophoresis-inductively coupled plasma mass spectrometry( CE-ICP-MS) was developed.To measure the total of heavy metals of copper(Cu), lead(Pb), chromium(Cr), cadmium(Cd) and arsenic(As) in oyster and scallops and the content of different forms of arsenic and lead compounds in the sample. Making risk assessment respectively, which will provide a scientific basis to eat shellfish seafood safely and protect the life and health of human beings.Methods:1. To establish extraction method about six kinds of arsenic compounds To weigh a certain amount of dry shellfish samples in round bottom flask accurately, adding CH3OH-H2 O mixed liquid to liquid extraction, microwave extraction. The extract was removed by centrifugation and the supernatant N2 was blown to the near dry. The buffer solution was diluted to the appropriate concentration.2. To measure the optimum conditions about six kinds of different forms of arsenic compounds in CE–ICP-MS To measure effects of different extraction methods, adding methanol amount(0%, 2%, 3%, 4%, 5%, 5.5% and 6%(V / V) and H3BO3-Na2B4O7 buffered hybrid concentration(20:5.0, 30:7.5, 40:10.0 50:12.5).Whether they influence on the separation result of six arsenic compounds of As(III), DMA, MMA, As(V), As B and As C.3. To establish method of extraction about three kinds of lead compounds The extraction method of organic lead: To weigh a certain amount of dry shellfish samples in round bottom flask accurately, adding CH3OH-H2 O mixed liquid to liquid extraction, microwave assisted extraction. Collecting and extracting liquid, filtering and separating, repeating the operation once, collecting the two filter liquid to obtain the organic lead extract. The extraction methods of inorganic lead: Adding acetic acid in the remaining residues in the microwave method to extract, the same collection of extraction, filtration, repeat the above operation once, two times to collect filter. The two extracts are mixed together, nitrogen blow to the near dry, with a small amount of buffer dilution to be measured, adding chelating agent for a certain period of time, into the CE-ICP-MS.4. To measure the optimum conditions about three kinds of different forms of lead compounds in CE–ICP-MS The effects of buffer system, adding methanol concentration(0.5%, 1%, 1.5%, 2%, 2.5% and 3% and 4%(V / V), CTAB(0.2, 0.3, 0.4, 0.5 and 0.6mmo1/L), the value of p H(8.60-9.10) and separation voltage(-11)-(-15),whether they influence on the separation result of three forms of lead compounds Pb(II), TEL and TML.5. Dietary consumption survey Take 24 hour dietary review method to conduct a questionnaire survey and the method of multistage stratified random sampling, a review of 24 h dietary survey on the residents who eats oysters and scallops and other shellfish products, collecting the consumption, consumption data recorded by accounting method.6. Results analysis method To calculate content of different forms of arsenic and lead in the samples, using spss17.0 analysis software, doing chi-square test and variance analysis, to analysis different kinds and seasonal distribution of content of arsenic and lead in the samples. To use the point evaluation method, calculating health risk index(HI)that two kinds of shellfish of arsenic, lead, and their different forms is obtained dietary intake and making risk assessment.Results:1 To establish a method for the determination of arsenic and lead compounds in different forms of shellfish1.1 To establish CE-ICP-MS phyphenated techniques for the determination of shellfish of six arsenic compounds about As(III),As(V), MMA, DMA, As B and As C separation method, in p H=9.10, voltage 18 k V, 40 mmol / L H3BO3-10mmol/LNa2B4O7 mixed buffer solution, into 10 s can complete separation of six arsenic compounds..1.2 To establish CE-ICP-MS phyphenated techniques for determination of three lead compounds of Pb(II), TEL and TML separation method in shellfish, in p H=8.90, 17.5 mmol/L Na2B4O7 L- 70 mmol/L H3BO3- 0.4 mmol/L CTAB mixed buffer solution, separation voltage of capillary electrophoresis for-13 k V, under the condition of sample 12 s, three kinds of lead compounds in 20 min to achieve good separation effect.2 Distribution of heavy metal content in different categories2.1 shellfish samples As(III), As(V), MMA, DMA, As B and As C detection rate comparison of six kinds of arsenic compounds Shellfish samples in Qingdao a few large farmers market in scallop and oyster DMA detection rate is higher, the difference was statistically significant(c2= 8.417, P = 8.417), scallops also detected in As(V) and arsenic compounds such As As B, upon examination had statistical significance(c 2 = 5.096, P = 0.024; c 2 = 3.245, P = 0.018), the other three kinds of no statistically significant difference were observed in the arsenic compounds(As( III) : the c 2 = 0.996, P = 0.318; MMA: c 2 = 0.250, P = 0.617; As C: c 2 = 0.542, P = 0.216).2.2 Pb(II), TEL and shellfish samples the TML three lead compounds such as detection rate comparison Shellfish samples in Qingdao a few large farmers market in scallop and oyster of Pb(II) detection rate is higher, the TML has detected in scallops, TEL have detected in the oyster, see table 12. Upon examination, no statistically significant difference were observed in the three kinds of lead compounds(Pb(II) : the c 2 = 2.545, P = 0.028; the TML: c 2 = 1.188, P = 0.552; TEL: c 2 = 0.0373, P = 0.830).2.3 A culture zones shellfish samples of copper(Cu), lead(Pb), chromium(Cr), cadmium(Cd) and arsenic(As) of five kinds of heavy metal contentContent in scallop is higher than the average content of oysters, the Cr content is the highest and lowest respectively detected in scallops in the body; Oyster samples slightly higher than the average contents of Cu Cu content in scallops, scallops in the highest levels, the lowest levels were detected in the oyster; Scallops sample of Cr, As, Cd and Pb were higher than the average content of oyster content of three kinds of heavy metal content of highest and lowest levels were found in samples of scallops, respectively, A Cr, As, Cd and Pb in scallop concentration difference is bigger.3 Risk assessment of shellfish seafood intake3.1 To make risk assessment on six kinds of arsenic compounds(As(III), the As(V), MMA, DMA, As B and As C) in shellfish samples Acquisition of Qingdao city several major farmers market in oysters and scallops, to calculate the risk quotient(HQ) on different forms of arsenic and lead compounds. The results showed that in the oyster and scallop HQ of DMA is less than 1 and have less risk; in scallop HQ of As(V) and As B is less than 1 and have less risk; other forms of arsenic compounds are not detected.3.2 To make risk assessment on three kinds of lead compounds(Pb(II), TEL and TML) in shellfish samples To calculate the risk quotient(HQ) Pb(II) is less than 1 in oysters and scallops and less risk; the lead compounds of TEL and TML has not been checked out.3.3 To make risk assessment on five kinds of heavy metals of copper(Cu), lead(Pb), chromium(Cr), cadmium(Cd) and arsenic(As) in shellfish samples In Qingdao a culture area to measure the heavy metals including copper(Cu), lead(Pb), chromium(Cr), cadmium(Cd) and arsenic(As) in shellfish, the risk quotient(HQ) of the five kinds of heavy metals in the oyster are less than 1 and have less risk; calculating the risk quotient(HQ) of scallops on five kinds of heavy metals, risk quotient(HQ) of Cr and Cd are greater than 1 and have greater risk but copper(Cu), lead(Pd), and arsenic(As) are less than 1 and have less risk for people health.In Qingdao in shellfish beds, copper(Cu), lead(Pb), chromium(Cr), cadmium(Cd) and heavy metals such As arsenic(As), risk business HQ in oysters are less than 1, less risky; Calculated scallops in five kinds of heavy metal Cr and the risk of Cd in HQ is greater than 1, risk; Copper(Cu), lead(Pb), and risk of heavy metals such As arsenic(As) is less than 1 HQ.Conclusions:1. The established method is stable, high recovery rate, the operation is simple, the sensitivity and precision meet the test.2. The type and content of heavy metals in different kinds of shellfish is different, the content of heavy metals in different sampling sites and seasons are also different.3. The problem of heavy metal pollution exists in most foods, according to the detection of the current market shellfish samples in the content of heavy metals to exclude the possibility of artificially added, they don’t pose a hazard to people living temporarily but the long-term follow-up of the impact of pollution on human health remains to be further studied.